Monday, August 08, 2011

Beyond Peak Oil

In the United States more than 40 percent of gasoline contains ethanol additive. The fuel is produced in huge fermenters the size of blimps, by fermenting a mash of corn or rye with yeast. Ethanol as a biofuel has a bad reputation. One hectare (2.47 acres) of corn produces less than 4,000 liters of ethanol a year, and 8,000 liters of water are required to produce a liter of ethanol. Besides, crops grown for ethanol take away valuable farmland for food production. The last growing season marked the first time US farmers harvested more corn for ethanol production than for use as animal feed. One of the adverse consequences of the biofuel boom is that it is driving up food prices. For this reason, many environmentalists now believe that growing energy plants is the wrong approach.

Scientists now rave about a new, green revolution. Using genetic engineering and sophisticated breeding and selection methods, biochemists are transforming blue and green algae into tiny factories for oil, ethanol and diesel. Algae do not require any farmland. Sun, saltwater, a little fertilizer and carbon dioxide are all the undemanding little organisms need to thrive. And because they consume about as much CO2 during photosynthesis as is later released when the oil they produce is burned, algae-based fuels are also climate neutral. In contrast to ethanol, the end product is not a low-quality fuel, but a highly pure product that contains no sulfur or benzene. "You could put our product in your car." Algae are also astonishingly productive. A hectare of sunny desert covered with algae vats can yield almost eight times as much biofuel per unit of biomass in a year than corn grown for energy purposes. To obtain the oil, the algae must be harvested and the oil extracted in a complex process. To overcome this obstacle, other scientists are developing algae that don't even have to be harvested. Instead, they essentially ooze the fuel of the future. Evolution has not yielded anything that produces biofuel from CO2 on a large scale, explains biologist Venter, "which is why we simply have to build it." The bioengineers' tools include culture mediums, incubators and, most importantly, databases containing the DNA sequences of thousands of microorganisms. Robertson and his team search the databases for promising gene fragments, which they then isolate and inject into the genetic material of blue algae.

But will the laboratory creations really work as well in open fields as they do in the lab? Calculations show that some algae plants will likely consume more fertilizer and energy per hectare than grain crops. And the carbon dioxide in the air won't be enough to feed the microalgae. Scientists estimate that a commercial algae fuel plant would require about 10,000 cubic meters of CO2 a day. Whether and how large amounts of the gas could be derived from the exhaust gases of large coal power plants, for example, and then brought to the algae farms, remains unclear. The farms could also require enormous tracts of land. In a recent article in the journal Science, researchers at Wageningen University in the Netherlands calculated that, in theory, an area the size of Portugal would have to be filled with algae pools to satisfy Europe's current fuel needs. A "leap in micro-algae technology" is needed to at least triple productivity, say experts.

Pyle and Robertson are convinced that this increase is possible. They insist that algae technology can be used to meet a significant portion of our energy requirements in the future. "There is certainly enough non-arable land with enough solar radiation and enough CO2 and water sourcing in the world," says Robertson. Another important advantage, he adds, is that algae-based fuel could easily be pumped into the oil industry's existing pipelines and refineries, and that cars and aircraft would not have to be modified to accommodate the biofuel.

From Der Spiegel

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